Excavation and spoil calculator
Soil expands when you dig it. The hole and the pile are different volumes, and skips are sized for the pile.
kg/m3
Spoil to remove
48.00m³
- Volume of the hole
- 38.40
- Weight of the spoil
- 69.12 tonnes
- Skips needed
- 6
- 20-tonne truck loads
- 4
- Spoil in cubic yards
- 62.78
Show the working
- Length = 8
- Width = 4
- Depth = 1.2
- Ground type = 25
- In-situ density = 1800
- Skip size = 8
- Volume of the hole = 8 * 4 * 1.2 = 38.4
- Spoil to remove = 38.4 * (1 + 25/100) = 48
- weight = 38.4 * 1800 = 69 120
- Weight of the spoil = 69 120 / 1000 = 69.12
- Skips needed = ceil(48 / 8) = 6
- Spoil in cubic yards = 48 / 0.764554857984 = 62.7816
- 20-tonne truck loads = ceil(69.12 / 20) = 4
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- spoil volume = dig volume x (1 + bulking factor)
Skips are usually charged by weight as well as volume, and heavy clay hits the weight limit long before the skip is full.
Always check for buried services before digging.